I've used powdered detergent bleach, blue RV stuff, and enzyme packets. I've also cleaned many, many (many) groovers. In my experience blue RV stuff works okay. The enzyme packets work on par, maybe a touch better. The powdered laundry detergent seems to work the best for me (also seems the easiest to clean), though many ppl use way too much of it since they put a little in every time they poo.
Though for cleaning considerations, I typically feed them Mexican food.